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        1 2     

  Subjects -> VETERINARY SCIENCE (Total: 176 journals)
Acta Scientiae Veterinariae     Open Access  
Acta Veterinaria     Open Access  
Acta Veterinaria Brno     Open Access   (Followers: 1)
Acta Veterinaria Hungarica     Full-text available via subscription   (Followers: 1)
Acta Veterinaria Scandinavica     Open Access   (Followers: 1)
Advances in Animal Biosciences     Full-text available via subscription   (Followers: 5)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 5)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 9)
American Journal of Animal and Veterinary Sciences     Open Access   (Followers: 7)
American Journal of Primatology     Hybrid Journal   (Followers: 5)
American Journal of Veterinary Research     Full-text available via subscription   (Followers: 14)
Anatomia, Histologia, Embryologia: Journal of Veterinary Medicine Series C     Hybrid Journal   (Followers: 2)
Animal Behaviour     Hybrid Journal   (Followers: 197)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 6)
Animal Health Research Reviews     Hybrid Journal   (Followers: 4)
Animal Reproduction Science     Hybrid Journal   (Followers: 4)
Animals     Open Access   (Followers: 5)
Annales UMCS, Medicina Veterinaria     Open Access  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annual Review of Animal Biosciences     Full-text available via subscription   (Followers: 4)
Anthrozoos : A Multidisciplinary Journal of The Interactions of People & Animals     Full-text available via subscription   (Followers: 5)
Archives of Animal Nutrition     Hybrid Journal   (Followers: 4)
Archivos de Medicina Veterinaria     Open Access   (Followers: 1)
Arquivo Brasileiro de Medicina Veterinária e Zootecnia     Open Access   (Followers: 1)
Asian Journal of Poultry Science     Open Access   (Followers: 4)
Atatürk Üniversitesi Veteriner Bilimleri Dergisi     Open Access  
Australian Equine Veterinarian     Full-text available via subscription   (Followers: 1)
Australian Veterinary Journal     Hybrid Journal   (Followers: 10)
Avances en Ciencias Veterinarias     Open Access  
Avian Diseases     Full-text available via subscription   (Followers: 4)
Avian Diseases Digest     Full-text available via subscription   (Followers: 3)
Avian Pathology     Hybrid Journal   (Followers: 2)
Bangladesh Journal of Animal Science     Open Access  
Bangladesh Journal of Veterinary Medicine     Open Access  
BMC Veterinary Research     Open Access   (Followers: 5)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 6)
Bulletin of Animal Health and Production in Africa     Full-text available via subscription  
Bulletin of the Veterinary Institute in Pulawy     Open Access  
Canadian Journal of Veterinary Research     Full-text available via subscription   (Followers: 4)
Case Reports in Veterinary Medicine     Open Access   (Followers: 3)
Ciência Rural     Open Access   (Followers: 2)
Companion Animal     Full-text available via subscription   (Followers: 4)
Domestic Animal Endocrinology     Hybrid Journal   (Followers: 3)
Equine Health     Full-text available via subscription  
Equine Veterinary Education     Hybrid Journal   (Followers: 7)
Equine Veterinary Journal     Hybrid Journal   (Followers: 9)
Ethiopian Veterinary Journal     Open Access   (Followers: 2)
Eurasian Journal of Veterinary Sciences     Open Access   (Followers: 1)
Human & Veterinary Medicine - International Journal of the Bioflux Society     Open Access   (Followers: 5)
ILAR Journal     Hybrid Journal  
In Practice     Full-text available via subscription   (Followers: 3)
Indian Journal of Animal Sciences     Open Access   (Followers: 5)
Indian Journal of Veterinary Anatomy     Full-text available via subscription   (Followers: 3)
International Journal for Agro Veterinary and Medical Sciences     Open Access   (Followers: 3)
International Journal of Livestock Research     Open Access  
International Journal of Veterinary Science and Medicine     Open Access   (Followers: 1)
InVet     Open Access  
Irish Veterinary Journal     Open Access   (Followers: 2)
ISRN Veterinary Science     Open Access  
Journal of Veterinary Science & Technology     Open Access   (Followers: 3)
Journal of Advanced Veterinary and Animal Research     Open Access   (Followers: 4)
Journal of Animal Behaviour and Biometeorology     Open Access   (Followers: 1)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Applied Animal Nutrition     Hybrid Journal   (Followers: 3)
Journal of Avian Medicine and Surgery     Full-text available via subscription   (Followers: 4)
Journal of Equine Veterinary Science     Hybrid Journal   (Followers: 8)
Journal of Exotic Pet Medicine     Full-text available via subscription   (Followers: 2)
Journal of Experimental and Applied Animal Sciences     Open Access   (Followers: 1)
Journal of Feline Medicine & Surgery     Hybrid Journal   (Followers: 4)
Journal of Research in Forestry, Wildlife and Environment     Open Access  
Journal of Small Animal Practice     Hybrid Journal   (Followers: 8)
Journal of the American Veterinary Medical Association     Full-text available via subscription   (Followers: 21)
Journal of the Hellenic Veterinary Medical Society     Full-text available via subscription   (Followers: 2)
Journal of the South African Veterinary Association     Open Access   (Followers: 1)
Journal of Venomous Animals and Toxins     Open Access   (Followers: 3)
Journal of Veterinary Advances     Open Access   (Followers: 4)
Journal of Veterinary Behavior: Clinical Applications and Research     Hybrid Journal   (Followers: 3)
Journal of Veterinary Cardiology     Full-text available via subscription   (Followers: 4)
Journal of Veterinary Diagnostic Investigation     Hybrid Journal   (Followers: 4)
Journal of Veterinary Emergency and Critical Care     Hybrid Journal   (Followers: 10)
Journal of Veterinary Internal Medicine     Hybrid Journal   (Followers: 12)
Journal of Veterinary Medical Education     Partially Free   (Followers: 8)
Journal of Veterinary Medicine     Open Access   (Followers: 3)
Journal of Veterinary Medicine and Animal Health     Open Access   (Followers: 1)
Journal of Veterinary Pharmacology and Therapeutics     Hybrid Journal   (Followers: 4)
Journal of Veterinary Science & Medical Diagnosis     Full-text available via subscription   (Followers: 1)
Journal of Zoo and Aquarium Research     Open Access  
Journal of Zoo and Wildlife Medicine     Full-text available via subscription   (Followers: 2)
Kenya Veterinarian     Full-text available via subscription   (Followers: 1)
kleintier konkret     Hybrid Journal  
Livestock     Full-text available via subscription   (Followers: 1)
Macedonian Veterinary Review     Open Access   (Followers: 3)
MEDIA PETERNAKAN - Journal of Animal Science and Technology     Open Access   (Followers: 1)
Medical Mycology     Open Access   (Followers: 2)
Medical Mycology Case Reports     Open Access  
Microbes and Health     Open Access   (Followers: 2)
New Zealand Veterinary Journal     Full-text available via subscription   (Followers: 7)
New Zealand Veterinary Nurse     Full-text available via subscription   (Followers: 2)
Nigerian Veterinary Journal     Open Access  
Onderstepoort Journal of Veterinary Research     Open Access   (Followers: 2)

        1 2     

Journal Cover Veterinary Microbiology
   [10 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0378-1135 - ISSN (Online) 1873-2542
     Published by Elsevier Homepage  [2563 journals]   [SJR: 1.221]   [H-I: 75]
  • Replication kinetics and shedding of very virulent Marek's Disease virus
           and vaccinal Rispens/CVI988 virus during single and mixed infections
           varying in order and interval between infections
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Tanzila Islam , Stephen W. Walkden Brown , Katrin G. Renz , A.F.M. Fakhrul Islam , Sithara Ralapanawe
      Vaccination is thought to contribute to an evolution in virulence of the Marek's disease virus (MDV) as vaccines prevent disease but not infection. We investigated the effects of co-infections at various intervals between Rispens/CVI988 vaccine virus (Rispens) and very virulent MDV (vvMDV) on the replication and shedding of each virus. The experiment used 600 ISA Brown layer chickens in 24 isolators with all treatments replicated in two isolators. Chickens were vaccinated with Rispens and/or challenged with the vvMDV isolate 02LAR on days 0, 5, or 10 post hatching providing vaccination to challenge intervals (VCI) of -10, -5, 0, 5 or 10 days with the negative values indicating challenge prior to vaccination. Peripheral blood lymphocytes (PBL), feathers and isolator exhaust dust were sampled between 7 and 56 days post infection (dpi) and subjected to quantitative real-time polymerase chain reaction (qPCR) to differentiate the two viruses. Overall Rispens significantly reduced the viral load of vvMDV in PBL and feather cells and shedding in dust. Similarly vvMDV significantly reduced the viral load of Rispens in PBL and feather cells but not in dust. VCI significantly influenced these relationships having strong positive and negative associations with load of vvMDV and Rispens respectively. Differences between the two viruses and their effects on each other were greatest in PBL and feathers, and least in dust. This study expands our understanding of the interaction between pathogenic and vaccinal viruses following vaccination with imperfect vaccines and has implications for selection of appropriate samples to test for vaccination success.


      PubDate: 2014-08-18T17:04:54Z
       
  • Alternative sampling strategies for passive classical and African swine
           fever surveillance in wild boar
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Anja Petrov , Ulrich Schotte , Jana Pietschmann , Carolin Dräger , Martin Beer , Helena Anheyer-Behmenburg , Katja Goller , Sandra Blome
      In view of the fact that African swine fever (ASF) was recently introduced into the wild boar population of the European Union and that classical swine fever (CSF) keeps reoccurring, targeted surveillance is of utmost importance for early detection. Introduction of both diseases is usually accompanied by an increased occurrence of animals found dead. Thus, fallen wild boar are the main target for passive surveillance. However, encouraging reporting by hunters and sampling of these animals is difficult. Partly, these problems could be solved by providing a pragmatic sampling approach. For this reason, we assessed the applicability of three different dry/semi-dry blood swabs, namely a cotton swab, a flocked swab, and a forensic livestock swab, for molecular swine fever diagnosis. After nucleic acid extraction using manual and automated systems, routine quantitative real-time polymerase chain reactions (qPCR) were carried out. Results obtained from swabs or their fragments were compared to results generated from EDTA blood. It was shown that reliable detection of both pathogens was possible by qPCR. Shifts in genome copy numbers were observed, but they did not change the qualitative results. In general, all swabs were suitable, but the forensic swab showed slight advantages, especially in terms of cutting and further storage. Robustness of the method was confirmed by the fact that different extraction methods and protocols as well as storage at room temperature did not have an influence on the final outcome. Taken together, swab samples could be recommended as a pragmatic approach to sample fallen wild boar.


      PubDate: 2014-08-18T17:04:54Z
       
  • Application of real-time PCR to detect Aleutian Mink Disease Virus on
           environmental farm sources
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): A. Prieto , J.M. Díaz-Cao , R. Fernández-Antonio , R. Panadero , P. Díaz , C. López , P. Morrondo , P. Díez-Baños , G. Fernández
      The Aleutian Mink Virus (AMDV) causes the Aleutian Mink Disease (AMD) or Mink Plasmacytosis, a disease responsible of high economic losses for industry worldwide. Despite there is evidence of the environmental persistence of the virus, there is not literature on the detection of this virus in environmental samples in farms and this fact would have great importance in the control programs of the disease. In order to detect contamination caused by AMDV on farms, several environmental samples were taken and examined using qPCR. 93.9% of samples taken from farms confirmed to be infected tested positive. The virus was also detected on a farm which, despite having no previous positive results, was sharing personnel with an infected farm. All samples taken from AMD-free farms tested negative, including a farm where an eradication procedure by stamping out had been performed during the preceding months. Higher contamination levels were observed in samples from those surfaces in direct contact with animals. These results are the first demonstration of environmental contamination in farms, hitherto suggested by epidemiological evidences, caused by AMDV on surfaces, furniture and equipments inside mink farms. qPCR is an useful tool for evaluating the spread of AMDV into the environment, and it may have important applications within the disease control programs


      PubDate: 2014-08-18T17:04:54Z
       
  • Equine Infectious Anemia Virus in Japan: Viral isolates V70 and V26 are of
           North American not Japanese origin
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): Jianbao Dong , Frank R. Cook , Wei Zhu
      The virulent and attenuated equine infectious anemia virus (EIAV) isolates V70 and V26 are reported as originating from Japan in a number of high profile publications resulting in their inclusion as “Asian viruses” in many subsequent phylogenetic and epidemiological studies. However, the widespread perception that V70 and V26 are Japanese is probably incorrect as the original published literature coupled with genomic analysis demonstrate these viruses are almost certainly derived from the North America strain EIAVWyoming strain.


      PubDate: 2014-08-18T17:04:54Z
       
  • Development of antibodies to and PCR detection of Ehrlichia spp. in dogs
           following natural tick exposure
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): Lindsay A. Starkey , Anne W. Barrett , Ramaswamy Chandrashekar , Brett A. Stillman , Phyllis Tyrrell , Brendon Thatcher , Melissa J. Beall , Jeff M. Gruntmeir , James H. Meinkoth , Susan E. Little
      Dogs exposed to ticks in the southern US may become infected with multiple species of Ehrlichia. To better define infection risk, blood samples collected from 10 dogs infested with ticks via a natural infestation model were evaluated by blood smear examination, PCR, patient-side ELISAs (SNAP® 4Dx® and SNAP® 4Dx® Plus), IFA, and peptide based ELISA for evidence of infection with Ehrlichia canis, E. chaffeensis, and/or E. ewingii. Although morulae were rarely identified in blood smears, every dog (10/10) became infected with Ehrlichia spp. as evidenced by nested PCR detection of E. chaffeensis (7/10) and E. ewingii DNA (10/10); real-time PCR detection of E. chaffeensis (0/10) and E. ewingii (9/10); seroconversion on two different patient-side ELISAs (4/10 or 10/10); seroconversion on IFA to E. canis (10/10, maximum inverse titer=128-4,096, GMTMAX =548.7) and E. chaffeensis (10/10, maximum inverse titer=1,024-32,768, GMTMAX= 4,096); and seroconversion on peptide specific ELISA to E. chaffeensis VLPT (7/10) and E. ewingii p28 (9/10). Rickettsemia with E. chaffeensis and E. ewingii, as determined by nested PCR, persisted in dogs for an average of 3.2 or 30.5 days, respectively. Ehrlichia canis was not detected in any dog by any method, and no dogs developed signs of clinical disease. Our data suggest that in areas where ticks are common, dogs are at high risk of infection with Ehrlichia spp., particularly E. ewingii and E. chaffeensis, and can serve as a sentinel for monitoring for the presence of these zoonotic pathogens


      PubDate: 2014-08-18T17:04:54Z
       
  • Highly pathogenic avian influenza virus (H5N8) in domestic poultry and its
           relationship with migratory birds in South Korea during 2014
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): Jipseol Jeong , Hyun-Mi Kang , Eun-Kyoung Lee , Byung-Min Song , Yong-Kuk Kwon , Hye-Ryoung Kim , Kang-Seuk Choi , Ji-Ye Kim , Hyun-Jeong Lee , Oun-Kyong Moon , Wooseog Jeong , Jida Choi , Jong-Ho Baek , Yi-Seok Joo , Yong Ho Park , Hee-Soo Lee , Youn-Jeong Lee
      Highly pathogenic H5N8 avian influenza viruses (HPAIVs) were introduced into South Korea during 2014, thereby caused outbreaks in wild birds and poultry farms. During the 2014 outbreak, H5N8 HPAIVs were isolated from 38 wild birds and 200 poultry farms (up to May 8, 2014). To better understand the introduction of these viruses and their relationships with wild birds and poultry farm, we analyzed the genetic sequences and available epidemiological data related to the viruses. Genetic analysis of 37 viruses isolated from wild birds and poultry farms showed that all of the isolates belonged to clade 2.3.4.6 of the hemagglutinin (HA) gene, but comprised two distinct groups. During the initial stage of the outbreak, identical isolates from each group were found in wild birds and poultry farms near Donglim Reservoir, which is a resting site for migratory birds, thereby indicating that two types of H5N8 HPAIVs were introduced into the lake at the same time. Interestingly, the one group of H5N8 HPAIV predominated around Donglim Reservoir, and the predominant virus was dispersed by wild birds among the migratory bird habitats in the western region of South Korea as time passed, and it was also detected in nearby poultry farms. Furthermore, compared with the results of the annual AIV surveillance of captured wild birds, which has been performed since 2008, more HPAIVs were isolated and H5 sero-prevalence was also detected during the 2014 outbreak. Overall, our results strongly suggest that migratory birds played a key role in the introduction and spread of viruses during the initial stage of the 2014 outbreak.


      PubDate: 2014-08-18T17:04:54Z
       
  • Transcriptome analysis of CNS immediately before and after the detection
           of PrPSc in SSBP/1 sheep scrapie
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): Anton G. Gossner , John Hopkins
      Sheep scrapie is a transmissible spongiform encephalopathy (TSE), progressive and fatal neurodegenerative diseases of the central nervous system (CNS) linked to the accumulation of misfolded prion protein, PrPSc. New Zealand Cheviot sheep, homozygous for the VRQ genotype of the PRNP gene are most susceptible with an incubation period of 193 days with SSBP/1 scrapie. However, the earliest time point that PrPSc can be detected in the CNS is 125 days (D125). The aim of this study was to quantify changes to the transcriptome of the thalamus and obex (medulla) at times immediately before (D75) and after (D125) PrPSc was detected. Affymetrix gene arrays were used to quantify gene expression in the thalamus and Illumina DGE-tag profiling for obex. Ingenuity Pathway Analysis was used to help describe the biological processes of scrapie pathology. Neurological disease and Cancer were common Bio Functions in each tissue at D75; inflammation and cell death were major processes at D125. Several neurological receptors were significantly increased at D75 (e.g. CHRNA6, GRM1, HCN2), which might be clues to the molecular basis of psychiatric changes associated with TSEs. No genes were significantly differentially expressed at both D75 and D125 and there was no progression of events from earlier to later time points. This implies that there is no simple linear progression of pathological or molecular events. There seems to be a step-change between D75 and D125, correlating with the detection of PrPSc, resulting in the involvement of different pathological processes in later TSE disease


      PubDate: 2014-08-18T17:04:54Z
       
  • Avian pathogenic Escherichia coli ΔtonB mutants are safe and
           protective live-attenuated vaccine candidates
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Karen M. Holden , Glenn F. Browning , Amir H. Noormohammadi , Philip Markham , Marc S. Marenda
      Avian pathogenic E. coli (APEC) cause colibacillosis, a serious respiratory disease in poultry. Most APEC strains possess TonB-dependent outer membrane transporters for the siderophores salmochelin and aerobactin, which both contribute to their capacity to cause disease. To assess the potential of iron transport deficient mutants as vaccine candidates, the tonB gene was deleted in the APEC wild type strain E956 and a Δfur (ferric uptake repressor) mutant of E956. The growth of the ΔtonB and ΔtonB/Δfur mutants was impaired in iron-restricted conditions, but not in iron-replete media. Day old chicks were exposed to aerosols of the mutants to assess their efficacy as live attenuated vaccines. At day 18, the birds were challenged with aerosols of the virulent parent strain E956. Both mutants conferred protection against colibacillosis; weight gains and lesion scores were significantly different between the vaccinated groups and an unvaccinated challenged control group. Thus mutation of iron uptake systems can be used as a platform technology to generate protective live attenuated vaccines against extraintestinal E. coli infections, and potentially a range of Gram negative pathogens of importance in veterinary medicine.


      PubDate: 2014-08-18T17:04:54Z
       
  • New aspects in the biology of Photobacterium damselae subsp. piscicida:
           pili, motility and adherence to solid surfaces
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Sara Remuzgo-Martínez , María Lázaro-Díez , Daniel Padilla , Belinda Vega , Fátima El Aamri , José Manuel Icardo , Félix Acosta , José Ramos-Vivas
      We describe for the first time the presence of pilus-like structures on the surface of Photobacterium damselae subsp. piscicida (Phdp). The hint to this discovery was the ability of one strain to hemagglutinate human erythrocytes. Further analysis of several Phdp strains ultrastructure by electron microscopy revealed the presence of long, thin fibers, similar to pili of other Gram negative bacteria. These appendages were also observed and photographed by scanning, transmission electron microscopy and immunofluorescence. Although this fish pathogen has been described as non-motile, all strains tested exhibit twitching motility, a flagella-independent type IV-dependent form of bacterial translocation over surfaces. As far as we are aware, the movement of Phdp bacteria on semi-solid or solid surfaces has not been described previously. Moreover, we speculate that Phdp twitching motility may be involved in biofilm formation. Microscopic examination of Phdp biofilms by microscopy revealed that Phdp biofilm architecture display extensive cellular chaining and also bacterial mortality during biofilm formation in vitro. Based on our results, standardized analyses of Phdp surface appendages, biofilms, motility and their impact on Phdp survival, ecology and pathobiology are now feasible
      Graphical abstract image

      PubDate: 2014-08-18T17:04:54Z
       
  • Bacillus sp. LT3 improves the survival of gnotobiotic brine shrimp
           (Artemia franciscana) larvae challenged with Vibrio campbellii by
           enhancing the innate immune response and by decreasing the activity of
           shrimp-associated vibrios
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Yufeng Niu , Tom Defoirdt , Kartik Baruah , Tom Van de Wiele , Shuanglin Dong , Peter Bossier
      Bacteria belonging to the genus Bacillus are amongst the most intensively studied group of bacteria for use as probiotics in aquaculture. However, the exact mechanism of action of these bacteria is often not well described, and the microbiota that are naturally present in cultures of test organisms often compromise the interpretation of the results. The present study aimed to evaluate the putative probiotic effect of Bacillus sp. LT3 in a model system with gnotobiotic brine shrimp Artemia franciscana larvae. The strain significantly increased the survival of brine shrimp larvae challenged with V. campbellii when administered 6h before the challenge. Under these conditions, LT3 was able to colonize the brine shrimp gastrointestinal tract and to decrease the in vivo pathogen activity as indicated by the bioluminescence of the V. campbellii associated with brine shrimp larvae. In order to investigate the effect of the Bacillus strain on the innate immune system of the brine shrimp larvae, prophenoloxidase and transglutaminase mRNA levels were monitored, while heat shock protein 70 mRNA levels were measured as an indicator of physiological stress. Interestingly, 12h after challenge, the prophenoloxidase mRNA level in the larvae pre-treated with LT3 and challenged with V. campbellii was approximately 8-fold higher than in the other treatments. Further, a decreased mRNA level of transglutaminase gene and heat shock protein 70 gene suggested that pretreatment with LT3 results in less stress and tissue damage in the brine shrimp larvae upon V. campbellii challenge. These results indicated that Bacillus sp. LT3 could improve the survival of brine shrimp larvae when challenged with pathogenic V. campbellii, both by decreasing the in vivo activity of the pathogen and by priming the innate immune response through activating the prophenoloxidase system.


      PubDate: 2014-08-18T17:04:54Z
       
  • Growth of Mannheimia haemolytica: inhibitory agents and putative mechanism
           of inhibition
    • Abstract: Publication date: Available online 15 August 2014
      Source:Veterinary Microbiology
      Author(s): Abirami Kugadas , Jessica Poindexter , Mee-La Lee , Jegarubee Bavananthasivam , Douglas R. Call , Kelly A. Brayton , Subramaniam Srikumaran
      Leukotoxin-producing Mannheimia haemolytica consistently causes fatal pneumonia in bighorn sheep (BHS) under experimental conditions. Surprisingly, by culture methods, it has been isolated from pneumonic BHS lungs less frequently than other bacteria. However, in one study PCR assays detected M. haemolytica from over 70% of the pneumonic lung samples that were negative for this organism by culture, suggesting that the growth of M. haemolytica is inhibited by other bacteria. Previously, we have shown that Bibersteinia trehalosi inhibits the growth of M. haemolytica. Herein we report that 100% of a diverse panel of B. trehalosi isolates (n=55) tested in a bacterial competition assay inhibited the growth of M. haemolytica, suggesting that the inhibitory phenotype is conserved. Further, no plasmids were isolated from any of the 30 B. trehalosi isolates tested, suggesting that the effectors are chromosomally-encoded. An earlier study by us showed that Pasteurella multocida also inhibits the growth of M. haemolytica. However, M. haemolytica has not been isolated even from pneumonic BHS lungs that did not carry B. trehalosi or P. multocida. Consequently, we tested Staphylococcus spp., Streptococcus spp., and Escherichia coli, the bacteria that have been detected frequently in pneumonic BHS lungs, for possible inhibition of M. haemolytica. Neither the Staphylococcus spp. nor the Streptococcus sp. strains inhibited the growth of M. haemolytica. E. coli inhibited the growth of M. haemolytica by a proximity-dependent mechanism. Growth inhibition of M. haemolytica by several bacterial species is likely to contribute to the infrequent detection of this bacterium from pneumonic BHS lungs by culture


      PubDate: 2014-08-18T17:04:54Z
       
  • Authors’ response: Recognition sequence for DNA uptake in
           Haemophilus parasuis
    • Abstract: Publication date: Available online 12 August 2014
      Source:Veterinary Microbiology
      Author(s): Anna Bigas , M. Elena Garrido , Ana M. Pérez de Rozas , Ignacio Badiola , Jordi Barbé , Montserrat Llagostera



      PubDate: 2014-08-14T16:54:39Z
       
  • Relationships of bovine ephemeral fever epizootics to population immunity
           and virus variation
    • Abstract: Publication date: Available online 14 August 2014
      Source:Veterinary Microbiology
      Author(s): Lu-Jen Ting , Ming-Shiuh Lee , Shu-Hwae Lee , Hsiang-Jung Tsai , Fan Lee
      Bovine ephemeral fever is an arthropod-borne bovine viral disease caused by infection with bovine ephemeral fever virus which belongs to genus Ephemerovirus within the family Rhabdoviridae. In this study, serological data and virological information about the disease and the virus, spanning from 2001 to 2013, were employed to analyze the relationships of bovine ephemeral fever epizootics to population immunity and virus variation. National and regional surveillance data indicated that 2 of the 3 major epizootics and 87% regional outbreaks were associated with lower neutralizing antibody titers and immunity coverage, reflecting the importance of population immunity for the control of bovine ephemeral fever. Phylogenetic analysis and sequence comparison demonstrated that Taiwanese bovine ephemeral fever viruses were>96.0% and>97.6% similar to the East Asian isolates in nucleotide and amino acid sequences, respectively. These analyses supported that the Taiwanese viruses shared the same gene pool with the strains of the other East Asian countries, mainly Japan.


      PubDate: 2014-08-14T16:54:39Z
       
  • The waaL gene is involved in lipopolysaccharide synthesis and plays a role
           on the bacterial pathogenesis of avian pathogenic Escherichia coli
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Yue Han , Xiangan Han , Shaohui Wang , Qingmei Meng , Yuxi Zhang , Chan Ding , Shengqing Yu
      Avian pathogenic Escherichia coli (APEC) is a Gram-negative bacterium that causes avian colibacillosis, resulting in economically devastating to poultry industries worldwide. Lipopolysaccharide (LPS) has been identified as an important virulence factor of E. coli. The waaL gene encodes O-antigen ligase, which is responsible for attaching the O-antigen to lipid A-core oligosaccharide. In this study, a mutant strain ΔwaaL was constructed from APEC serotype 2 strain DE17. The mutant strain showed a decreased swimming motility and resistance to complement-mediated killing but a similar growth rate in the culture, compared with its parent strain. In addition, the mutant LPS demonstrated different patterns in SDS-PAGE followed by silver staining and western blotting. Besides, the mutant strain significantly decreased its adherence and invasion abilities to DF-1 cells, compared to its parent strain DE17. Deletion of the waaL gene in DE17 reduced the bacterial virulence by 42.2-fold in ducklings, based on measurement of the median lethal dose (LD50). Additional analysis indicated that deletion of the waaL gene increased the biofilm formation ability and reduced the resistance to environmental stress. These results suggest that the waaL gene functions on the APEC LPS synthesis and bacterial pathogenesis.


      PubDate: 2014-07-27T16:22:37Z
       
  • SNP genotyping of animal and human derived isolates of Mycobacterium avium
           subsp. paratuberculosis
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): James W. Wynne , Christie Beller , Victoria Boyd , Barry Francis , Jacek Gwoźdź , Marios Carajias , Hans G. Heine , Josef Wagner , Carl D. Kirkwood , Wojtek P. Michalski
      Mycobacterium avium subsp. paratuberculosis (MAP) is the aetiological agent of Johne's disease (JD), a chronic granulomatous enteritis that affects ruminants worldwide. While the ability of MAP to cause disease in animals is clear, the role of this bacterium in human inflammatory bowel diseases remains unresolved. Previous whole genome sequencing of MAP isolates derived from human and three animal hosts showed that human isolates were genetically similar and showed a close phylogenetic relationship to one bovine isolate. In contrast, other animal derived isolates were more genetically diverse. The present study aimed to investigate the frequency of this human strain across 52 wild-type MAP isolates, collected predominantly from Australia. A Luminex based SNP genotyping approach was utilised to genotype SNPs that had previously been shown to be specific to the human, bovine or ovine isolate types. Fourteen SNPs were initially evaluated across a reference panel of isolates with known genotypes. A subset of seven SNPs was chosen for analysis within the wild-type collection. Of the seven SNPs, three were found to be unique to paediatric human isolates. No wild-type isolates contain these SNP alleles. Interestingly, and in contrast to the paediatric isolates, three additional adult human isolates (derived from adult Crohn's disease patients) also did not contain these SNP alleles. Furthermore we identified two SNPs, which demonstrate extensive polymorphism within the animal-derived MAP isolates. One of which appears unique to ovine and a single camel isolate. From this study we suggest the existence of genetic heterogeneity between human derived MAP isolates, some of which are highly similar to those derived from bovine hosts, but others of which are more divergent.


      PubDate: 2014-07-27T16:22:37Z
       
  • Severe generalized skin lesions due to mixed infection with Sporothrix
           schenkii and Dermatophilus congolensis in a bull from Jos, Nigeria
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): J.S. Dalis , H.M. Kazeem , J.K.P. Kwaga , C.N. Kwanashie
      Sporothrix schenkii and Dermatophilus congolensis were isolated from a bull with severe generalized skin lesions. The lesions were thick, crusty and scabby on the dorsal part while few scabby and several nodular lesions were seen on the lower limbs especially the thighs. Scab samples and exudates from the nodules were aseptically collected and processed for bacteriology and mycology. Gram stained smears revealed Gram-positive, filamentous organism that had longitudinal and transverse septa suggestive of D. congolensis. Colonies on 5% defibrinated sheep blood agar were small, rough, grayish-white, β-hemolytic and adherent to the medium. It was catalase positive, urease positive and fermented glucose and maltose but not sucrose, lactose, mannitol, sorbitol and xylose. Colonies on Sabouraud's dextrose agar were small, round, white and opaque, delicate and smooth. It liquefied gelatin and fermented glucose and sucrose but not galactose, menite, and glycerin. The isolate was Gram-positive, cigar-shaped and yeast-like suggestive of S. schenkii. Dermatophilosis is common in domesticated ruminants while sporotrichosis is very rare in cattle. This may be the first report of bovine sporotrichosis from Africa.


      PubDate: 2014-07-27T16:22:37Z
       
  • IFC - Aims & Scope, EDB, Publication Information
    • Abstract: Publication date: 6 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 1–2




      PubDate: 2014-07-27T16:22:37Z
       
  • Erratum to “Innate immunity to recombinant QseC, a bacterial
           adrenergic receptor, may regulate expression of virulence genes of avian
           pathogenic Escherichia coli” [Vet. Microbiol. 171 (2014)
           236–241]
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Atul A. Chaudhari , Subhashinie Kariyawasam



      PubDate: 2014-07-27T16:22:37Z
       
  • Use of a proposed antimicrobial susceptibility testing method for
           Haemophilus parasuis
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Denise Ann E. Dayao , Marco Kienzle , Justine S. Gibson , Patrick J. Blackall , Conny Turni
      The aim of this study was to examine the antimicrobial susceptibility of 97 Haemophilus parasuis cultured from Australian pigs. As there is no existing standard antimicrobial susceptibility technique available for H. parasuis, methods utilising the supplemented media, BA/SN for disc diffusion and test medium broth (TMB) for a microdilution technique, were initially evaluated with the reference strains recommended by the Clinical and Laboratory Standards Institute. The results of the media evaluation suggested that BA/SN and TMB can be used as suitable media for susceptibility testing of H. parasuis. The proposed microdilution technique was then used with 97 H. parasuis isolates and nine antimicrobial agents. The study found that Australian isolates showed elevated minimum inhibitory concentrations (MICs) for ampicillin (1%), penicillin (2%), erythromycin (7%), tulathromycin (9%), tilmicosin (22%), tetracycline (31%) and trimethoprim-sulfamethoxazole (40%). This study has described potential antimicrobial susceptibility methods for H. parasuis and has detected a low percentage of Australian H. parasuis isolates with elevated antimicrobial MICs.


      PubDate: 2014-07-27T16:22:37Z
       
  • Sheep as an important source of E. coli O157/O157:H7 in Turkey
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Yilmaz Emre Gencay
      Escherichia coli O157:H7 is a globally important foodborne pathogen and has been mainly associated with cattle as the reservoir. However, accumulating data shows the importance of sheep as an E. coli O157:H7 vehicle. The presence of E. coli O157/O157:H7 in recto-anal mucosal swap and carcass sponge samples of 100 sheep brought to the slaughterhouse in Kirikkale were analyzed over a year. Molecular characteristics (stx 1 , stx 2 , eaeA, hly, lpfA1-3, espA, eae-α1, eae-α2, eae-β, eae-β1, eae-β2, eae-γ1, eae-γ2/θ, stx1 c , stx1 d , stx2 c , stx2 d , stx2 e , stx2 f , stx2 g , bla ampC, tet(A), tet(B), tet(C), tet(D), tet(E), tet(G), sul1, sul2, floR, cmlA, strA, strB and aadA) of 79 isolates were determined and minimum inhibitory concentrations of 20 different antibiotics were investigated. E. coli O157/O157:H7 was found in 18% of sheep included in the study and was more prevalent in yearlings than lambs and mature sheep, and male than female sheep, though none of the categories (season, sex or age range) had significant effect on prevalence. Furthermore, Shiga-toxigenic E. coli (STEC) O157:H7 was determined in 2% and 8% of sheep feces and carcasses, respectively. Additionally, lpfA1-3 and eae-γ1 were detected in all isolates. None of the isolates showed resistance against investigated antibiotics, even though 4 sorbitol fermenting E. coli O157 isolates were positive for tet(A), sul1 and aadA. This is the first study in Turkey that reveals the potential public health risk due to the contamination of sheep carcasses with potentially highly pathogenic STEC O157:H7 strains.


      PubDate: 2014-07-27T16:22:37Z
       
  • Quantitative PCR analysis of Mycoplasma suis shedding patterns during
           experimental infection
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Stefanie Dietz , Sarah-Lena Mack , Katharina Hoelzle , Katja Becker , Carolin Jannasch , Julia Stadler , Mathias Ritzmann , Ludwig E. Hoelzle
      The uncultivable hemotrophic bacterium Mycoplasma suis causes infectious anemia in pigs worldwide. The mechanisms by which M. suis is transmitted from pig to pig are largely unknown. Thus, the present study aimed at investigating urine, feces, saliva, nasal and vaginal secrets as well as environmental samples for the presence of M. suis DNA to get insights into potential transmission routes. Seven pigs were experimentally infected with M. suis KI3806. Samples were taken for 8 days post infection (p.i.). A quantitative LightCycler msg1 PCR was used to detect and quantify M. suis. Shedding was found in saliva as well as nasal and vaginal secrets from day 6 p.i. on with a quantity of 3.4×102 to 2.7×105 M. suis/swab. In urine M. suis DNA could be detected in 100.0% of the samples from day 6 p.i. on with a quantity of 4.7×102 to 6.3×105 M. suis per mL. When shedding patterns were correlated to the median bacterial blood loads shedding was observed at loads of 2.0×109–7.0×1010 M. suis per mL blood. No M. suis DNA could be amplified from feces. Dust and water samples of the pig drinking troughs were positive for M. suis on days 2 and 6 post infection, air samples were M. suis-negative throughout the experiment. Our results indicate that blood independent direct transmission as well as indirect transmission via environmental contamination could play a role in the epidemiology of M. suis infections.


      PubDate: 2014-07-27T16:22:37Z
       
  • Further evidence for the existence of environmental and host-associated
           species of coagulase-negative staphylococci in dairy cattle
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Anneleen De Visscher , Karlien Supré , Freddy Haesebrouck , Ruth N. Zadoks , Veerle Piessens , Els Van Coillie , Sofie Piepers , Sarne De Vliegher
      Coagulase-negative staphylococci (CNS) are abundantly present in the dairy farm environment and on bovine skin and mucosae. They are also the most prevalent bacteria causing bovine intramammary infections (IMI). Reservoirs and transmission routes of CNS are not yet fully unraveled. The objectives of this study were to explore the distribution of CNS in parlor-related extramammary niches and to compare it to the distributions of CNS causing IMI in those herds. Niches that were targeted in this study were cows’ teat apices, milking machine unit liners, and milker's skin or gloves. Each of the three herds had its own CNS microbiota in those niches. The most prevalent species in the parlor-related extramammary niches were Staphylococcus cohnii, S. fleurettii, and S. equorum in the first, second, and third herd, respectively, whereas S. haemolyticus and S. sciuri were found in all herds. S. cohnii and S. fleurettii, as well as S. haemolyticus, which was present in each herd, were also frequently found in milk samples. By contrast, S. chromogenes, S. simulans, and S. xylosus favored the mammary gland, whereas S. equorum was more common in the parlor-associated niches. Within each herd, species distribution was similar between teat apices and milking machine unit liners. In conclusion, some of the extramammary niches related to the milking process might act as infection sources for IMI-causing CNS. This study provides further evidence that the group of CNS species is comprised of environmental, opportunistic and host-adapted species which differ in ecology.


      PubDate: 2014-07-27T16:22:37Z
       
  • Intra-farm risk factors for Mycoplasma hyopneumoniae colonization at
           weaning age
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Maria Pieters , Greg S. Cline , Brian J. Payne , Cesar Prado , Jonathan R. Ertl , Aaron K. Rendahl
      The objective of this study was to identify intra-farm risk factors that affected the colonization with Mycoplasma hyopneumoniae at weaning age. Three farrow-to-wean farms were visited at least 5 times each. An average of 54 piglets were sampled at each visit and assayed by means of real-time PCR in nasal swabs. The proportion of PCR positive piglets was evaluated as a response to several variables including dam's PCR status, piglet serological status, and local climatic conditions during the lactation period, as well as other factors. All piglets at weaning age were negative to M. hyopneumoniae in 2 of the 3 farms. M. hyopneumoniae positive piglets were demonstrated in 5 of 7 weaning groups in 1 farm. The proportion of M. hyopneumoniae positive piglets in each weaning group at the positive farm was correlated with the proportion of positive dams in the group. The prevalence of M. hyopneumoniae at weaning increased with the piglet's age in the groups where at least one dam was positive. These results highlight the influence of the sow in the sow-to-piglet colonization process, as previously reported, and contribute to a more comprehensive understanding of the epidemiology of M. hyopneumoniae infections.


      PubDate: 2014-07-27T16:22:37Z
       
  • A bacterial engineered glycoprotein as a novel antigen for diagnosis of
           bovine brucellosis
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Andrés E. Ciocchini , Diego A. Rey Serantes , Luciano J. Melli , Leticia S. Guidolin , Jeremy A. Iwashkiw , Sebastián Elena , Cristina Franco , Ana M. Nicola , Mario F. Feldman , Diego J. Comerci , Juan E. Ugalde
      Brucellosis is a highly contagious zoonosis that affects livestock and human beings. Laboratory diagnosis of bovine brucellosis mainly relies on serological diagnosis using serum and/or milk samples. Although there are several serological tests with different diagnostic performance and capacity to differentiate vaccinated from infected animals, there is still no standardized reference antigen for the disease. Here we validate the first recombinant glycoprotein antigen, an N-formylperosamine O-polysaccharide-protein conjugate (OAg-AcrA), for diagnosis of bovine brucellosis. This antigen can be produced in homogeneous batches without the need of culturing pathogenic brucellae; all characteristics that make it appropriate for standardization. An indirect immunoassay based on the detection of anti O-polysaccharide IgG antibodies in bovine samples was developed coupling OAg-AcrA to magnetic beads or ELISA plates. As a proof of concept and to validate the antigen, we analyzed serum, whole blood and milk samples obtained from non-infected, experimentally infected and vaccinated animals included in a vaccination/infection trial performed in our laboratory as well as more than 1000 serum and milk samples obtained from naturally infected and S19-vaccinated animals from Argentina. Our results demonstrate that OAg-AcrA-based assays are highly accurate for diagnosis of bovine brucellosis, even in vaccinated herds, using different types of samples and in different platforms. We propose this novel recombinant glycoprotein as an antigen suitable for the development of new standard immunological tests for screening and confirmatory diagnosis of bovine brucellosis in regions or countries with brucellosis-control programs.


      PubDate: 2014-07-27T16:22:37Z
       
  • Suitability of faeces and tissue samples as a basis for non-invasive
           sampling for African swine fever in wild boar
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): H.C. de Carvalho Ferreira , E. Weesendorp , S. Quak , J.A. Stegeman , W.L.A. Loeffen
      A challenging aspect of ASFV control in wild boar populations is the design and implementation of effective surveillance and monitoring programmes, both for early warning, and to determine the ongoing epidemiological situation in an infected population. Testing blood samples requires invasive sampling strategies like hunting or capture of wild boar. Besides being biased towards healthy animals, such strategies are also linked to further spread of the virus. Non-invasive sampling strategies would increase the reliability of surveillance of ASFV in wild boar populations, without the negative side effects. This study evaluates the potential of faeces and tissue samples as a basis for non-invasive sampling strategies for ASFV in wild boar. In the acute phase (0–21 days after infection), in comparison with virus detection in blood, virus can be detected in faeces 50–80% of the time. This percentage decreases to below 10% for the subacute/chronic phase. ASFV DNA is quite stable in faeces. Half-lives range from more than 2 years at temperature up to 12°C, to roughly 15 days at temperatures of 30°C. In tissue samples, stored at 20°C, half-lives mostly range from 1.7 to 7.4 days. The sample of preference is the spleen, where the highest titres and highest half-life of ASFV DNA are observed. The level and duration of excretion of ASFV in the faeces, combined with the stability of the DNA, suggest that sampling of faeces could be the basis for a non-invasive sampling strategy to monitor ASFV in wild boar.


      PubDate: 2014-07-27T16:22:37Z
       
  • EF1A interacting with nucleocapsid protein of transmissible
           gastroenteritis coronavirus and plays a role in virus replication
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Xin Zhang , Hongyan Shi , Jianfei Chen , Da Shi , Changlong Li , Li Feng
      Transmissible gastroenteritis coronavirus (TGEV) is an enteropathogenic coronavirus that causes diarrhea in pigs, which is correlated with high morbidity and mortality in suckling piglets. Using the method of GST pull-down with the nucleocapsid (N), N protein was found to interact with swine testes (ST) cells elongation factor 1-alpha (EF1A), an essential component of the translational machinery with an important role in cells. In vitro and in virus-infected cells interaction was then confirmed by co-precipitation. Knockdown of EF1A impairs N protein proliferation and TGEV replication in host cell. It was demonstrated that EF1A plays a role in TGEV replication. The present study thus provides a protein-related information that should be useful for underlying mechanism of coronavirus replication.


      PubDate: 2014-07-27T16:22:37Z
       
  • Evaluation of the efficacy of a new modified live porcine reproductive and
           respiratory syndrome virus (PRRSV) vaccine (Fostera PRRS) against
           heterologous PRRSV challenge
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Changhoon Park , Hwi Won Seo , Kiwon Han , Ikjae Kang , Chanhee Chae
      The objective of this study was to evaluate a new modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine (Fostera PRRS, Zoetis, Florham, NJ, USA) that was based on a virulent US PRRSV isolate (P129) attenuated using CD163-expressing cell lines. Sixty-four PRRSV-seronegative 3-week-old pigs were randomly divided into the following four groups: vaccinated challenged (group 1), vaccinated unchallenged (group 2), unvaccinated challenged (group 3), and unvaccinated unchallenged (group 4). The pigs in groups 1 and 2 were immunized with a 2.0mL dose of modified live PRRSV vaccine at 21 days of age, according to the manufacturer's recommendations. At 56 days of age (0 days post-challenge), the pigs in groups 1 and 3 were inoculated intranasally with 3mL of tissue culture fluid containing 105 50% tissue culture infective dose (TCID50)/mL of PRRSV (SNUVR090851 strain, fourth passage in MARC-145 cells). Vaccinated challenged pigs exhibited significantly lower (P <0.05) respiratory scores, viremia, macroscopic and microscopic lung lesion scores, and PRRSV-antigen with interstitial pneumonia than unvaccinated challenged pigs. The induction of PRRSV-specific IFN-γ-SCs by the new modified live PRRSV vaccine produced a protective immune response, leading to the reduction of PRRSV viremia. Although the new modified live PRRSV vaccine is not effective against heterologous PRRSV challenge, the new modified live PRRSV vaccine was able to reduce the levels of viremia and nasal shedding, and severity of PRRSV-induced lesions after challenging virus under experimental conditions.


      PubDate: 2014-07-27T16:22:37Z
       
  • Synergetic effects of subgroup J avian leukosis virus and
           reticuloendotheliosis virus co-infection on growth retardation and
           immunosuppression in SPF chickens
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Xuan Dong , Sidi Ju , Peng Zhao , Yang Li , Fanfeng Meng , Peng Sun , Zhizhong Cui
      To further understand the effect of co-infection of subgroup J avian leukosis virus (ALV-J) and reticuloendotheliosis virus (REV) in specific-pathogen-free (SPF) white leghorn chickens, the experiment was made to study the pathogenicity, the weight of body and immune organs, response to newcastle disease virus (NDV) and avian influenza virus subtype H9 (AIV-H9) vaccination. Chickens were randomly divided into four groups, which includes injection groups (REV, ALV-J, REV plus ALV-J), and negative control group. The pathogenesis experiments indicated that chickens co-infected with REV and ALV-J had significantly higher mortality rate than those of the chickens infected with REV or ALV-J alone (P <0.05). Chickens inoculated with REV and ALV-J had significantly lower weights than chickens in all other groups (P <0.05). There were no significant differences between the two single infection groups and co-infection group (P >0.05) on bursa and thymus over body wt ratios, however, chickens co-infected with REV and ALV-J had significantly lower titers than REV-infected chickens and ALV-J-infected chickens on HI antibody titers to ND and AIV-H9 after vaccination (P <0.05). These findings suggested that the co-infection of REV and ALV-J caused more serious growth retardation and immunosuppression in SPF chickens.


      PubDate: 2014-07-27T16:22:37Z
       
  • Estimation of hepatitis E virus (HEV) pig seroprevalence using ELISA and
           Western blot and comparison between human and pig HEV sequences in Belgium
           
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Damien Thiry , Axel Mauroy , Claude Saegerman , Isabelle Thomas , Magali Wautier , Cora Miry , Guy Czaplicki , Dirk Berkvens , Nicolas Praet , Wim van der Poel , Roland Cariolet , Bernard Brochier , Etienne Thiry
      Zoonotic transmission of hepatitis E virus (HEV) is of special concern, particularly in high income countries were waterborne infections are less frequent than in developing countries. High HEV seroprevalences can be found in European pig populations. The aims of this study were to obtain prevalence data on HEV infection in swine in Belgium and to phylogenetically compare Belgian human HEV sequences with those obtained from swine. An ELISA screening prevalence of 73% (95% CI 68.8–77.5) was determined in Belgian pigs and a part of the results were re-evaluated by Western blot (WB). A receiver operating characteristic curve analysis was performed and scenarios varying the ELISA specificity relative to WB were analysed. The seroprevalences estimated by the different scenarios ranged between 69 and 81% and are in agreement with the high exposure of the European pig population to HEV. Pig HEV sequences were genetically compared to those detected in humans in Belgium and a predominance of genotype 3 subtype f was shown in both swine and humans. The high HEV seroprevalence in swine and the close phylogenetic relationships between pig and human HEV sequences further support the risk for zoonotic transmission of HEV between humans and pigs.


      PubDate: 2014-07-27T16:22:37Z
       
  • Genetic characterization and serological prevalence of swine hepatitis E
           virus in Shandong province, China
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Xin-jie Wang , Qin Zhao , Feng-lin Jiang , Bao-yuan Liu , Ji-nan Zhao , Lu Dang , Ya-ni Sun , Yang Mu , Shu-qi Xiao , Cheng-bao Wang , Walter H. Hsu , Lihong Liu , Frederik Widén , En-Min Zhou
      Hepatitis E virus (HEV), the causative agent of hepatitis E, is classified into four major genotypes (1 to 4) and swine is the main natural reservoir for genotypes 3 and 4. In this study, a total of 106 bile samples from a slaughterhouse in the Shandong province of China were tested for the partial ORF2 gene of HEV by RT-nPCR to determine the virus genotypes, and two indirect ELISA were developed for the detection of swine HEV specific IgM and IgG antibodies in 980 serum samples from 24 farms, in order to investigate the seroprevalence. Thirty-two out of 106 (30.2%) bile samples were positive for HEV and a high degree of partial ORF2 sequence similarity (86.8–100%) was observed among 20 samples. The viral sequences belonged to genotype 4, subtypes 4a and 4d. One complete genome sequence of a subtype 4d HEV was further determined and characterized. The seroprevalence of HEV IgG and IgM antibodies was 100% (24/24) and 41.7% (10/24) for herds, and 66.4% (651/980) and 1.6% (16/980) for the individual pigs, respectively. These results suggested a high prevalence of genotype 4 of swine HEV infection both in swine farms and at the slaughterhouse in Shandong province, which further raise public-health concerns for zoonosis and pork safety.


      PubDate: 2014-07-27T16:22:37Z
       
  • Novel Kobuvirus species identified from black goat with diarrhea
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Jae-Ku Oem , Myoung-Heon Lee , Kyoung-Ki Lee , Dong-Jun An
      In this study, a caprine kobuvirus was identified from the diarrheal feces of a Korean black goat. The virus had an 8291-nucleotide-long genome excluding the poly(A) tail, and the genome contained a large open reading frame of 7437bp, which encoded a putative polyprotein precursor of 2479 amino acids. Full-genome sequence analysis indicated that the caprine kobuvirus was most closely related to porcine kobuvirus, with 75.9% amino acid similarity and 70.1% nucleotide similarity. The predicted secondary structure of the 5′ terminus (110-bp region) of strain 12Q108 consisted of three stem-loop domains. The first loop sequence of 12Q108 differed from that of strain Y-1-CH1 at one nucleotide position. The full genome substitution rates of caprine kobuvirus were assessed and the time to the most recent common ancestor (TMRCA) of caprine kobuivirus was compared with that of kobuvirus strains from other species. The rate of evolutionary substitution was determined to be 6.40×10−3 substitutions per site per year, and the TMRCA was determined to be 149.6 years for kobuviruses. Furthermore, the caprine kobuvirus TMRCA was determined to be 48.8 years (95% highest posterior density: 8.3–88.4).


      PubDate: 2014-07-27T16:22:37Z
       
  • Adaptation of a natural reassortant H5N2 avian influenza virus in mice
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Qunhui Li , Xuan Wang , Lei Zhong , Xiaoquan Wang , Zhongtao Sun , Zhao Gao , Zhu Cui , Jie Zhu , Min Gu , Xiaowen Liu , Xiufan Liu
      It is reported that the H5N2 highly pathogenic avian influenza virus A/chicken/Hebei/1102/2010 (HB10) is a natural reassortant between circulating H5N1 and endemic H9N2 influenza viruses. To evaluate the potential of its interspecies transmission, the wild-type HB10 was adapted in mice through serial lung passages. Increased virulence was detectable in 5 sequential lung passages in mice and a highly virulent mouse-adapted strain (HB10-MA) with a 50% mouse lethal dose of 102.5 50% egg infectious dose was obtained in 15 passages. The virulence and the replication efficiency of HB10-MA in mice were significantly higher than those of HB10 while HB10-MA grew faster and to significantly higher titers than HB10 in MDCK and A549 cells. Only five amino acid mutations in four viral proteins (HA-S227N, PB2-Q591K, PB2-D701N, PA-I554V and NP-R351K) of HB10-MA virus were found when compared with those of HB10, indicating that they may be responsible for the adaptation of the novel reassortant H5N2 avian influenza virus in mice with increased virulence and replication efficiency. The results in this study provide helpful insights into the pathogenic potential of novel reassortant H5N2 viruses to mammals that deserves further attentions.


      PubDate: 2014-07-27T16:22:37Z
       
  • Molecular epidemiology of H9N2 influenza viruses in Northern Europe
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Erika Lindh , Christine Ek-Kommonen , Veli-Matti Väänänen , Antti Vaheri , Olli Vapalahti , Anita Huovilainen
      Low pathogenic avian influenza viruses are maintained in wild bird populations throughout the world. Avian influenza viruses are characterized by their efficient ability to reassort and adapt, which enables them to cross the species barrier and enhances their zoonotic potential. Influenza viruses of the H9N2 subtype appear endemic among poultry in Eurasia. They usually exist as low-pathogenic strains and circulate between wild bird populations, poultry and birds sold at live bird markets. Direct transmission of H9N2 viruses, with receptor specificities similar to human influenza strains, to pigs and humans has been reported on several occasions. H9N2 virus was first encountered in Finland in 2009, during routine screening of hunted wild waterfowl. The next year, H9N2 influenza viruses were isolated from wild birds on four occasions, including once from a farmed mallard. We have investigated the relationship between the reared and wild bird isolates by sequencing the hemagglutinin and the neuraminidase genes of the Finnish H9N2 viruses. Nucleotide sequence comparison and phylogenetic analyses indicate that H9N2 was transmitted from wild birds to reared birds in 2010, and that highly identical strains have been circulating in Europe during the last few years.


      PubDate: 2014-07-27T16:22:37Z
       
  • A severe equine herpesvirus type 1 (EHV-1) abortion outbreak caused by a
           neuropathogenic strain at a breeding farm in northern Germany
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Armando Mario Damiani , Maren de Vries , Gitta Reimers , Sonja Winkler , Nikolaus Osterrieder
      A particularly severe equine herpesvirus type 1 (EHV-1) abortion outbreak occurred at a breeding farm in northern Germany. Sixteen of 25 pregnant mares that had received regular vaccination using an inactivated vaccine aborted and two gave birth to weak non-viable foals in a span of three months, with 89% of cases occurring within 40 days after the initial abortion case. Virological examinations revealed the presence of EHV-1 in all cases of abortion and serological follow-up in mares confirmed recent infection. Molecular studies identified a neuropathogenic variant (Pol/ORF30 A2254 to G2254) that belonged to geographical group 4 of EHV-1 isolates. The abortion outbreak was preceded by a case of mild ataxia of unknown cause in a mare that aborted four months after the ataxic episode. Although vaccination of pregnant mares did not prevent abortion, good EHV-1 immune status of the population at the time of outbreak may have had an impact in the failure of manifestation of the neurological form of the disease.


      PubDate: 2014-07-27T16:22:37Z
       
  • Experimental infection of house sparrows (Passer domesticus) with West
           Nile virus strains of lineages 1 and 2
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Javier Del Amo , Francisco Llorente , Elisa Pérez-Ramirez , Ramón C. Soriguer , Jordi Figuerola , Norbert Nowotny , Miguel Angel Jiménez-Clavero
      West Nile virus (WNV) is a zoonotic pathogen which is maintained in an enzootic cycle between mosquitoes and birds; humans, equines, other mammals and some bird species are dead-end hosts. Lineage 1 WNV strains have predominated in Europe since the 1960s. However, in 2004 lineage 2 strains emerged in Hungary and Russia, respectively, spreading since then to a number of neighbouring countries (e.g., Austria, Greece, Italy, Serbia and Romania). Wild bird mortality is a hallmark of North American WNV outbreaks, a feature uncommon in Europe. This study aimed to compare the course of infection of lineage 1 (NY99) and lineage 2 (Austria/2008) WNV strains in the house sparrow, a bird species common in Europe and North America. House sparrows were inoculated with either NY99 or Austria/2008 WNV strains, or sham-inoculated, and clinical and analytic parameters (viraemia, viral load, antibodies) were examined until 14 days after inoculation. Although all inoculated sparrows became infected, no mortality or clinical signs were observed due to the infection. However, the magnitude and duration of viraemia were higher for NY99 – than for Austria/2008 – infected birds. The house sparrow proved to be a competent host for both strains, although the competence index calculated for NY99 was higher than for Austria/2008. Viral load in tissues and swabs was also higher in NY99-inoculated sparrows. In conclusion, the house sparrow is a convenient avian model for studying host competence of WNV strains. The observed differences between NY99 and Austria/2008 strains might have important epidemiological consequences for disease incidence and dispersal capacity.


      PubDate: 2014-07-27T16:22:37Z
       
  • Generation, transmission and infectiosity of chicken MDV aerosols under
           experimental conditions
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Haiyu Hao , Chao Li , Yuyu Qiu , Fangshan Wang , Wenhao Ai , Jing Gao , Liangmeng Wei , Xiaoxia Li , Lingyu Sun , Jie Wu , Guiping Qin , Rong Li , Jiyuan Liu , Jing Lv , Rong Huang , Hairong Wang , Tongjie Chai
      To further investigate the airborne infection mechanism of Marek's disease virus (MDV), a MDV aerosol infection model was established, and the generation, transmission and infectiosity of MDV aerosols were monitored in this study. Two positive/negative pressure isolators, in which SPF chickens were raised, were connected with a closed conduit. Two repetitive trials, Trial 1 (T1) and Trial 2 (T2) were carried out for objective assessment. Air samples were collected using the AGI-30 sampler. Viral DNA in air samples and feather follicle samples were detected using real-time quantitative PCR (QRT-PCR). MDV in air and blood samples was detected by indirect immunofluorescence assay (IFA). In chickens of isolator A (MDV inoculation group), MDV was detected in feather follicles in 100% of the tested chickens at 6 days post inoculation (dpi) in both trials; and MDV was isolated from blood samples at 9–10dpi. MDV DNA was detected in air samples from isolator A at 12dpi in T1 and 14dpi in T2 and concentration of aerosolized MDV DNA was peaked at 3.84×106 copies/m3 air at 40dpi in T1, and 6.17×105 copies/m3 air at 38dpi in T2, respectively. Infectious MDV (cell culture) was isolated from isolator A at 17 in T1 and 19dpi in T2, respectively. MDV aerosol in Isolator B was almost same as isolator A. Viremia was detected in isolator B at 26–30dpi. The incidence of viremia in isolator B reached 70% at 3 months post inoculation. These results demonstrated that infected chicken could discharge virus, the MDV could form aerosols and infect neighboring chickens. Understanding the mechanism of generation and infection of MDV aerosols is helpful to prevent and control MD.


      PubDate: 2014-07-27T16:22:37Z
       
  • Detection of torque teno sus virus 1 and 2 in porcine tissues by in situ
           hybridization using multi-strained pooled probes
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Yao Lee , Chun-Ming Lin , Chian-Ren Jeng , Victor Fei Pang
      Porcine torque teno sus virus (TTSuV) has been suggested as a co-factor for the development of porcine circovirus-associated diseases. However, the pathogenic role of TTSuV is still inconclusive, and the target cell and tissue tropism of this virus are also ambiguous. In the present study, a multi-strained pooled probe-based in situ hybridization was established to detect the nucleic acids of TTSuV1 and TTSuV2 in the tissue. The strategy of using polymerase chain reaction-derived digoxigenin-labeled multi-strained pooled probe, instead of single-strained probe or oligonucleotide, was to overcome the fact of high sequence diversity among TTSuV strains and simultaneous infection with distinct strains of TTSuV in the same animal. The cell tropism and tissue distribution were evaluated by grading system with tissues from major organs. Lymphoid tissues, including superficial inguinal, mesenteric, and hilar lymph nodes, tonsil, intestinal lamina propria of mucosa and Peyer's patches, and sometimes spleen, generally contained higher levels of positive signals and are considered as the target sites for TTSuV. Morphologically, the distribution of TTSuV-positive signals had a strong correlation with the T lymphocyte zone. T lymphocytes are, thus, speculated as the major target cells for TTSuV.


      PubDate: 2014-07-27T16:22:37Z
       
  • Investigation into an outbreak of encephalomyelitis caused by a
           neuroinvasive porcine sapelovirus in the United Kingdom
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Alex Schock , Rajesh Gurrala , Harriet Fuller , Leo Foyle , Malte Dauber , Francesca Martelli , Sandra Scholes , Lisa Roberts , Falko Steinbach , Akbar Dastjerdi
      An outbreak of neurological disease in grower pigs characterised by ataxia and paraparesis was investigated in this study. The outbreak occurred 3–4 weeks post weaning in grower pigs which displayed signs of spinal cord damage progressing to recumbency. Pathology in the affected spinal cords and to a lesser extent in the brainstem was characterised by pronounced inflammation and neuronophagia in the grey matter. Molecular investigation using a pan-virus microarray identified a virus related to porcine sapelovirus (PSV) in the spinal cord of the two affected pigs examined. Analysis of 802 nucleotides of the virus polymerase gene showed the highest homology with those of viruses in the genus Sapelovirus of Picornaviridae. This PSV, strain G5, shared 91–93%, 67–69% and 63% nucleotide homology with porcine, simian and avian sapeloviruses, respectively. The nucleotide homology to other members of the Picornaviridae ranged from 41% to 62%. Furthermore, viral antigen was detected and co-localised in the spinal cord lesions of affected animals by an antibody known to react with PSV. In conclusion, clinical and laboratory observations of the diseased pigs in this outbreak are consistent with PSV-G5 being the causative agent. To the best of the authors’ knowledge, this is the first unequivocal report of polioencephalomyelitis in pigs by a neuroinvasive PSV in the United Kingdom.


      PubDate: 2014-07-27T16:22:37Z
       
  • Comparison of sow and/or piglet vaccination of 3 commercial porcine
           circovirus type 2 (PCV2) single-dose vaccines on pigs under experimental
           PCV2 challenge
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Yeonsu Oh , Hwi Won Seo , Changhoon Park , Chanhee Chae
      The objective of the present study was to compare the effect of sow and/or piglet vaccination regimen by three commercial porcine circovirus type 2 (PCV2) vaccines on pigs experimentally challenged with PCV2 at 84 days of age based on immunological, virological, and pathological evaluation. One hundred and nineteen piglets born to vaccinated or non-vaccinated sows were divided into 17 groups. A portion of the pigs with or without passively acquired immunity was vaccinated at 21 or 49 days of age. Regardless of the PCV2 vaccine, the combination of sow and pig (49 days of age) vaccinations significantly (P <0.05) reduced PCV2 viremia, induced higher log2 transformed neutralizing antibody titers, and resulted in higher proportion of CD4+CD8+IFN-γ+ lymphocyte subsets than the sow vaccination alone, the pig (21 or 49 days of age) vaccination alone, and the combination of sow and pig (21 days of age) vaccinations at various days post challenge. The results showed a significant negative correlation between maternally derived antibodies at the day of vaccination and the increment of antibody titers to PCV2 at 28 days post vaccination in the combination of sow and pig (21 days of age) vaccinations but not the combination of sow and pig (49 days of age) vaccinations. The combination of sow and pig (49 days of age) vaccinations could be more effective for controlling PCV2 infection if PCV2 the infection occurs during the growing-finishing period in herds. Optimal vaccination strategies must balance the advantage of delayed vaccination with the need to induce immunity prior to exposure to pathogens under field conditions.


      PubDate: 2014-07-27T16:22:37Z
       
  • Detection and distribution of torque teno sus virus 1 in porcine
           reproductive and respiratory syndrome virus positive/negative pigs
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Zhicheng Zhang , Yang Wang , Wei Dai , Dingzhen Dai
      To investigate the detection rate and distribution of torque teno sus virus 1 (TTSuV1) in porcine reproductive and respiratory syndrome virus (PRRSV) positive/negative pigs, 2384 pathological tissues samples collected from 6 provinces of Eastern China from 2010 to 2013 were amplified using previously published PRRSV and TTSuV1 primers. The presence and viral load of TTSuV1 were investigated in a wide range of samples from 5 PRRSV positive/negative 4-week-old pigs by real-time TaqMan PCR. TTSuV1 was detected in 65.3% of 1115 PRRSV-positive samples, and 47.2% of 1269 negative samples. Viral DNA was most commonly detected in the immune organs, including spleen, lung, pancreas, and mesenteric and inguinal lymph nodes, followed by serum, liver, kidney, trachea, anal swabs, nasal swabs and sex glands of PRRSV-positive or negative pigs. TTSuV1 DNA loads in PRRSV-positive pigs increased from 2 to 5 times in almost all the corresponding parts compared with PRRSV-negative pigs. Statistical analysis showed that PRRSV may have a synergistic effect with TTSuV1, and promote the replication and proliferation of TTSuV1.


      PubDate: 2014-07-27T16:22:37Z
       
  • VP6 genetic diversity, reassortment, intragenic recombination and
           classification of rotavirus B in American and Japanese pigs
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Douglas Marthaler , Tohru Suzuki , Kurt Rossow , Marie Culhane , James Collins , Sagar Goyal , Hiroshi Tsunemitsu , Max Ciarlet , Jelle Matthijnssens
      Rotavirus B (RVB) has been identified as a causative agent of diarrhea in rats, humans, cattle, lambs, and swine. Recently, 20 RVB VP7 genotypes were determined based on an 80% nucleotide percent cut-off value. In this study, we sequenced the RVB VP6 gene segment from 80 RVB positive swine samples from the United States and Japan. Phylogenetic analyses, using the 30 available RVB VP6 sequences from GenBank and our 80 novel RVB VP6 sequences, revealed a large genetic diversity of RVB strains, mainly in pigs. For classification purposes, pairwise identity frequency analyses suggested an 81% nucleotide percent cut-off value, resulting in 13 RVB VP6 (I) genotypes. In addition, an intragenic recombinant RVB VP6 segment was identified from Japan. Furthermore, the data indicates frequent reassortment events occurred between the porcine RVB VP7 and VP6 gene segments.


      PubDate: 2014-07-27T16:22:37Z
       
  • Pathogenesis of leptospirosis: Cellular and molecular aspects
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Ben Adler
      Leptospirosis is arguably the most widespread zoonosis; it is also a major cause of economic loss in production animals worldwide. At the level of the host animal or human, the progression of infection and the onset of disease are well documented. However, the mechanisms of pathogenesis at the cellular and molecular level remain poorly understood, mainly as a result of the lack of modern genetic tools for mutagenesis of pathogenic Leptospira spp. The recent development of transposon mutagenesis and the construction of a very small number of directed leptospiral mutants have identified a limited number of essential virulence factors. Perhaps surprisingly, many leptospiral proteins with characteristics consistent with a role in virulence have been shown to not be required for virulence in animal models, consistent with a high degree of functional redundancy in pathogenic Leptospira. A large number of putative adhesins has been reported in Leptospira, which interact with a range of host tissue components; however, almost none of these have been genetically confirmed as having an essential role in pathogenesis.


      PubDate: 2014-07-27T16:22:37Z
       
  • Re-identification of Aeromonas isolates from rainbow trout and incidence
           of class 1 integron and β-lactamase genes
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Vicente Vega-Sánchez , Fadua Latif-Eugenín , Edgardo Soriano-Vargas , Roxana Beaz-Hidalgo , María José Figueras , Ma. Guadalupe Aguilera-Arreola , Graciela Castro-Escarpulli
      Forty-eight Aeromonas isolates from rainbow trout previously identified by the 16S rDNA-RFLP technique were re-identified using 2 housekeeping genes (gyrB and rpoD). After sequencing the prevalences of the species were A. veronii (29.2%), A. bestiarum (20.8%), A. hydrophila (16.7%), A. sobria (10.4%), A. media (8.3%), A. popoffii (6.2%), A. allosaccharophila (2.1%), A. caviae (2.1%), A. salmonicida (2.1%) and one isolate (2.1%) belongs to a candidate new species “Aeromonas lusitana”. Coincident identification results to the 16S rDNA-RFLP technique were only obtained for 68.8% of the isolates. PCR amplification of the enterobacterial repetitive intergenic consensus (ERIC-PCR) indicated that the 48 isolates belonged to 33 different ERIC genotypes. Several genotypes were isolated from different farms and organs in the same fish, indicating a systemic dissemination of the bacteria. The presence of genes (bla IMP, bla CphA/IMIS, bla TEM, bla SHV and intI1) that encode extended-spectrum beta-lactamases (ESBLs), metallo-beta-lactamases (MBLs) and class 1 integrons were studied by PCR. Only 39.6% (19/48) of the strains showed the presence of one or more resistance genes. The gene bla CphA/IMIS was detected in 29.2% of the isolates, followed by the intI1 (6.2%) and bla SHV (4.2%) genes. The variable region of class 1 integrons of the 3 positive isolates was sequenced revealing the presence of the gene cassette aadA1 (aminoglycoside transferase) that plays a role in streptomycin/spectinomycin resistance.


      PubDate: 2014-07-27T16:22:37Z
       
  • Increasing prevalence of extended-spectrum cephalosporin-resistant
           Escherichia coli in food animals and the diversity of CTX-M genotypes
           during 2003–2012
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Lili Rao , Luchao Lv , Zhenling Zeng , Sheng Chen , Dandan He , Xiaojie Chen , Congming Wu , Yang Wang , Tong Yang , Peng Wu , Yahong Liu , Jian-Hua Liu
      The aim of this study was to investigate the trends and the diversity of CTX-M types of extended-spectrum β-lactamase (ESBL) in Escherichia coli isolated from food animals in China over a ten-year period. From 2003 to 2012, 2815 E. coli isolates collected from diseased animals (chickens, pigs, and waterfowl) were screened for the prevalence of CTX-M genes. CTX-M-positive isolates were tested for their susceptibilities to 10 antimicrobial agents and the clonal relationship of CTX-M-producing E. coli isolates was also assessed. Overall, 677 (20.1%) of the 2815 E. coli isolates carried CTX-M genes. Eighteen different types of CTX-M ESBLs were identified, with CTX-M-14, CTX-M-55, and CTX-M-65 being the most dominant genotypes. The occurrence of CTX-M-producing E. coli increased significantly from 5.7% in 2003–2005 to 35.3% in 2009–2012 (p <0.0001). High genetic heterogeneities were observed in the CTX-M-producing E. coli isolates. Most CTX-M-producing strains were also resistant to other classes of antimicrobials. Compared to isolates carrying CTX-M-9 subgroup of ESBLs, isolates carrying CTX-M-1 subgroup ESBLs showed significantly higher resistance rates to ceftazidime, amikacin, and fosfomycin (p <0.01). The study reported the dramatic increase of CTX-M ESBLs in E. coli isolated from animals overtime in China. The increasing incidence of CTX-M-55 with high hydrolytic activity against ceftazidime and the widely spread co-resistance in CTX-M-producing isolates alarm the serious antimicrobial resistance situation in China and highlight the need for urgent control strategies to limit the dissemination of those resistant genes in China.


      PubDate: 2014-07-27T16:22:37Z
       
  • Transmission of ESBL/AmpC-producing Escherichia coli from broiler chicken
           farms to surrounding areas
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): H. Laube , A. Friese , C. von Salviati , B. Guerra , U. Rösler
      Although previous studies have demonstrated high carriage of ESBL/AmpC-producing Escherichia coli in livestock, especially in broiler chickens, data on emission sources of these bacteria into the environment are still rare. Therefore, this study was designed to systematically investigate the occurrence of ESBL/AmpC-producing E. coli in slurry, air (inside animal houses), ambient air (outside animal houses) and on soil surfaces in the areas surrounding of seven ESBL/AmpC-positive broiler chicken fattening farms, including investigation of the possible spread of these bacteria via the faecal route and/or exhaust air into the environment. Seven German broiler fattening farms were each investigated at three points in time (3–36h after restocking, 14–18 and 26–35 days after housing) during one fattening period. The occurrence of ESBL/AmpC genes in the investigated samples was confirmed by PCR, detecting bla CTX-M, bla SHV, bla TEM and bla CMY-genes, and, if necessary, by sequencing and/or the disc diffusion method. The results showed a wide spread of ESBL/AmpC-producing E. coli in broiler farms, as well as emissions into the surroundings. 12 out of 14 (86%) slurry samples were positive for ESBL/AmpC-producing E. coli. Additionally, 28.8% (n =23/80) of boot swabs taken from various surfaces in the areas surrounding of the farms as well as 7.5% (n =3/40) of the exhaust air samples turned out to be positive for these microorganisms. Moreover, a small proportion of air samples from inside the barns were ESBL/AmpC-positive. By comparing selected isolates using pulsed field gel electrophoresis, we proved that faecal and airborne transfer of ESBL/AmpC-producing microorganisms from broiler fattening farms to the surrounding areas is possible. Two isolates from farm G2 (slurry and boot swab 50m downwind), two isolates from farm G3 (slurry and individual animal swab) as well as two isolates from farm G6 (air sample in the barn and air sample 50m downwind) showed 100% similarity in PFGE analysis.


      PubDate: 2014-07-27T16:22:37Z
       
  • Biofilm formation by coagulase-negative staphylococci: Impact on the
           
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Yannick D.N. Tremblay , Vincent Caron , Andréanne Blondeau , Serge Messier , Mario Jacques
      Coagulase-negative staphylococci (CNS) have traditionally been considered minor mastitis pathogens and are the bacteria most frequently isolated from intramammary infection. Previously, our laboratory demonstrated that a majority of CNS isolated from Canadian milk were able to form biofilm and this was strongly and positively associated with days in milk. Biofilms offer protection against antibiotics and disinfectants, and the presence of CNS biofilms near the end of the lactation cycle could have an impact on the prevention and recurrence of CNS infections in the next lactation cycle. The objective of this study was to investigate the effect of biofilm formation on efficacy of commonly used antibiotics and disinfectants against CNS. The minimal inhibitory concentration (MIC) and minimal biofilm eradication concentration (MBEC) of several CNS isolates were determined using microdilution method and the MBEC device, respectively. Biofilm cells were more resistant to a penicillin G/novobiocin combination and to ceftiofur than their planktonic counterparts and the increase in resistance ranged from 4× to 2048×. For the disinfectants, we determined the minimum contact time required for different teat disinfectants to eradicated planktonic cells and biofilms. The chlorhexidine-based teat disinfectants eradicated planktonic cells and biofilms within 30s. For iodine-based teat disinfectants, it took 2–10× longer to eradicate the biofilms than planktonic cells. In conclusion, CNS biofilms were less susceptible to antibiotics; however, chlorhexidine-based teat disinfectants were still effective against CNS biofilms. This reinforces the use of post-milking teat disinfectants as a preventive measure of intramammary infections.


      PubDate: 2014-07-27T16:22:37Z
       
  • Experimental infection of cats with Afipia felis and various Bartonella
           species or subspecies
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Bruno B. Chomel , Rickie W. Kasten , Matthew J. Stuckey , Edward B. Breitschwerdt , Ricardo G. Maggi , Jennifer B. Henn , Jane E. Koehler , Chao-chin Chang
      Based upon prior studies, domestic cats have been shown to be the natural reservoir for Bartonella henselae, Bartonella clarridgeiae and Bartonella koehlerae. However, other Bartonella species, such as Bartonella vinsonii subsp. berkhoffii, Bartonella quintana or Bartonella bovis (ex weissii) have been either isolated from or Bartonella DNA sequences PCR amplified and sequenced. In the late 1980s, before B. henselae was confirmed as the etiological agent of cat scratch disease, Afipia felis had been proposed as the causative agent. In order to determine the feline susceptibility to A. felis, B. vinsonii subsp. berkhoffii, Bartonella rochalimae, B. quintana or B. bovis, we sought to detect the presence of bacteremia and seroconversion in experimentally-inoculated cats. Most of the cats seroconverted, but only the cats inoculated with B. rochalimae became bacteremic, indicating that cats are not natural hosts of A. felis or the other Bartonella species or subspecies tested in this study.


      PubDate: 2014-07-27T16:22:37Z
       
  • A metallo-β-lactamase is responsible for the degradation of ceftiofur
           by the bovine intestinal bacterium Bacillus cereus P41
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Bruce D. Erickson , Christopher A. Elkins , Lisa B. Mullis , Thomas M. Heinze , R. Doug Wagner , Carl E. Cerniglia
      Ceftiofur is a highly effective veterinary cephalosporin, yet it is rapidly degraded by bacteria in the gut. The goal of this work was to directly determine the mechanism of ceftiofur degradation by the bovine intestinal isolate Bacillus cereus P41. B. cereus P41 was isolated from the feces of a cow that had not been treated with cephalosporins, and was found to rapidly degrade ceftiofur in culture. Analysis of spent culture media by HPLC/UV and HPLC/MS revealed one major metabolite of ceftiofur, with a negative ion m/z of 127. Comparison of ceftiofur, ceftriaxone, and cefpodoxime degradation suggested that the major stable ceftiofur metabolite was the thiofuroic acid group eliminated from the C-3 position of the drug after hydrolysis by β-lactamase. Genomic DNA from B. cereus P41 was cloned into Escherichia coli, and the transformants were screened for growth in the presence of ceftiofur. DNA sequencing of the plasmid pHSG299-BC-3 insert revealed the presence of a gene encoding a metallo-β-lactamase. Incubation of ceftiofur with either the E. coli transformant or a commercial B. cereus metallo-β-lactamase showed degradation of the drug and formation of the same major metabolite produced by B. cereus P41. These data demonstrate that a metallo-β-lactamase plays a major role in the degradation of ceftiofur by the bovine intestinal bacterium B. cereus P41.


      PubDate: 2014-07-27T16:22:37Z
       
  • Genetic relatedness of Brucella suis biovar 2 isolates from hares, wild
           boars and domestic pigs
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4
      Author(s): Zsuzsa Kreizinger , Jeffrey T. Foster , Zsuzsanna Rónai , Kinga M. Sulyok , Enikő Wehmann , Szilárd Jánosi , Miklós Gyuranecz
      Porcine brucellosis generally manifests as disorders in reproductive organs potentially leading to serious losses in the swine industry. Brucella suis biovar 2 is endemic in European wild boar (Sus scrofa) and hare (Lepus europeus, Lepus capensis) populations, thus these species may play a significant role in disease spread and serve as potential sources of infection for domestic pigs. The aim of this study was an epidemiologic analysis of porcine brucellosis in Hungary and a comparative analysis of B. suis bv. 2 strains from Europe using multiple-locus variable-number tandem repeat analysis (MLVA). MLVA-16 and its MLVA-11 subset were used to determine the genotypes of 68 B. suis bv. 2 isolates from Hungary and results were then compared to European MLVA genotypes. The analyses indicated relatively high genetic diversity of B. suis bv. 2 in Hungary. Strains isolated from hares and wild boars from Hungary showed substantial genetic divergence, suggesting separate lineages in each host and no instances of cross species infections. The closest relatives of strains from Hungarian wild boars and domestic pigs were mainly in the isolates from German and Croatian boars and pigs. The assessment of the European MLVA genotypes of wild boar isolates generally showed clustering based on geographic origin. The hare strains were relatively closely related to one another and did not cluster based on geographic origin. The limited relationships between geographic origin and genotype in isolates from hares might be the result of cross-border live animal translocation. The results could also suggest that certain B. suis strains are more adapted to hares. Across Europe, isolates from domestic pigs were closely related to isolates originating from both hares and wild boars, supporting the idea that wild animals are a source of brucellosis in domestic pigs.


      PubDate: 2014-07-27T16:22:37Z
       
  • IFC - Aims &amp; Scope, EDB, Publication Information
    • Abstract: Publication date: 27 August 2014
      Source:Veterinary Microbiology, Volume 172, Issues 3–4




      PubDate: 2014-07-27T16:22:37Z
       
 
 
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